lightning: add fakewallet (#134)

* lightning: add fakewallet

* make format

* fix mypy

* make backend configurable

* weird mypy

.env.example

@@ -21,6 +21,9 @@ TOR=TRUE
 
 MINT_PRIVATE_KEY=supersecretprivatekey
 
+# Supported: LNbitsWallet, FakeWallet
+MINT_LIGHTNING_BACKEND=LNbitsWallet
+
 MINT_SERVER_HOST=127.0.0.1
 MINT_SERVER_PORT=3338
 

cashu/core/settings.py

@@ -44,6 +44,7 @@ MINT_URL = env.str("MINT_URL", default=None)
 MINT_HOST = env.str("MINT_HOST", default="8333.space")
 MINT_PORT = env.int("MINT_PORT", default=3338)
 
+MINT_LIGHTNING_BACKEND = env.str("MINT_LIGHTNING_BACKEND", default="FakeWallet")
 MINT_DATABASE = env.str("MINT_DATABASE", default="data/mint")
 
 if not MINT_URL:

cashu/lightning/__init__.py

@@ -1,3 +1,3 @@
-# from cashu.lightning.lnbits import LNbitsWallet
-
-# WALLET = LNbitsWallet()
+# type: ignore
+from .fake import FakeWallet
+from .lnbits import LNbitsWallet

cashu/lightning/fake.py

@@ -0,0 +1,100 @@
+import asyncio
+import hashlib
+import random
+from datetime import datetime
+from typing import AsyncGenerator, Dict, Optional, Set
+
+from cashu.core.bolt11 import Invoice, decode, encode
+
+from .base import (
+    InvoiceResponse,
+    PaymentResponse,
+    PaymentStatus,
+    StatusResponse,
+    Wallet,
+)
+
+
+class FakeWallet(Wallet):
+    """https://github.com/lnbits/lnbits"""
+
+    queue: asyncio.Queue = asyncio.Queue(0)
+    paid_invoices: Set[str] = set()
+    secret: str = "FAKEWALLET SECRET"
+    privkey: str = hashlib.pbkdf2_hmac(
+        "sha256",
+        secret.encode(),
+        ("FakeWallet").encode(),
+        2048,
+        32,
+    ).hex()
+
+    async def status(self) -> StatusResponse:
+        return StatusResponse(None, 1337)
+
+    async def create_invoice(
+        self,
+        amount: int,
+        memo: Optional[str] = None,
+        description_hash: Optional[bytes] = None,
+        unhashed_description: Optional[bytes] = None,
+        **kwargs,
+    ) -> InvoiceResponse:
+        data: Dict = {
+            "out": False,
+            "amount": amount * 1000,
+            "currency": "bc",
+            "privkey": self.privkey,
+            "memo": memo,
+            "description_hash": b"",
+            "description": "",
+            "fallback": None,
+            "expires": kwargs.get("expiry"),
+            "timestamp": datetime.now().timestamp(),
+            "route": None,
+            "tags_set": [],
+        }
+        if description_hash:
+            data["tags_set"] = ["h"]
+            data["description_hash"] = description_hash
+        elif unhashed_description:
+            data["tags_set"] = ["d"]
+            data["description_hash"] = hashlib.sha256(unhashed_description).digest()
+        else:
+            data["tags_set"] = ["d"]
+            data["memo"] = memo
+            data["description"] = memo
+        randomHash = (
+            self.privkey[:6]
+            + hashlib.sha256(str(random.getrandbits(256)).encode()).hexdigest()[6:]
+        )
+        data["paymenthash"] = randomHash
+        payment_request = encode(data)
+        checking_id = randomHash
+
+        return InvoiceResponse(True, checking_id, payment_request)
+
+    async def pay_invoice(self, bolt11: str, fee_limit_msat: int) -> PaymentResponse:
+        invoice = decode(bolt11)
+
+        if invoice.payment_hash[:6] == self.privkey[:6]:
+            await self.queue.put(invoice)
+            self.paid_invoices.add(invoice.payment_hash)
+            return PaymentResponse(True, invoice.payment_hash, 0)
+        else:
+            return PaymentResponse(
+                ok=False, error_message="Only internal invoices can be used!"
+            )
+
+    async def get_invoice_status(self, checking_id: str) -> PaymentStatus:
+
+        paid = checking_id in self.paid_invoices
+        return PaymentStatus(paid or None)
+
+    async def get_payment_status(self, _: str) -> PaymentStatus:
+        return PaymentStatus(None)
+
+    async def paid_invoices_stream(self) -> AsyncGenerator[str, None]:
+        while True:
+            value: Invoice = await self.queue.get()
+            yield value.payment_hash

cashu/lightning/lnbits.py

@@ -1,5 +1,4 @@
 # type: ignore
-from os import getenv
 from typing import Dict, Optional
 
 import requests

cashu/mint/startup.py

@@ -1,22 +1,32 @@
 # startup routine of the standalone app. These are the steps that need
 # to be taken by external apps importing the cashu mint.
 
-import asyncio
+import importlib
 
 from loguru import logger
 
 from cashu.core.db import Database
 from cashu.core.migrations import migrate_databases
-from cashu.core.settings import CASHU_DIR, LIGHTNING, MINT_DATABASE, MINT_PRIVATE_KEY
+from cashu.core.settings import (
+    CASHU_DIR,
+    LIGHTNING,
+    MINT_DATABASE,
+    MINT_LIGHTNING_BACKEND,
+    MINT_PRIVATE_KEY,
+)
+from cashu.lightning.fake import FakeWallet  # type: ignore
 from cashu.lightning.lnbits import LNbitsWallet  # type: ignore
 from cashu.mint import migrations
 from cashu.mint.ledger import Ledger
 
+wallets_module = importlib.import_module("cashu.lightning")
+LIGHTNING_BACKEND = getattr(wallets_module, MINT_LIGHTNING_BACKEND)()
+
 ledger = Ledger(
     db=Database("mint", MINT_DATABASE),
     seed=MINT_PRIVATE_KEY,
     derivation_path="0/0/0/0",
-    lightning=LNbitsWallet(),
+    lightning=LIGHTNING_BACKEND,
 )
 
 
@@ -27,6 +37,7 @@ async def start_mint_init():
     await ledger.init_keysets()
 
     if LIGHTNING:
+        logger.info(f"Using backend: {MINT_LIGHTNING_BACKEND}")
         error_message, balance = await ledger.lightning.status()
         if error_message:
             logger.warning(

mypy.ini

@@ -1,2 +1,7 @@
 [mypy]
-exclude = /cashu/nostr/
+python_version = 3.9
+# disallow_untyped_defs = True
+ignore_missing_imports = True
+
+[mypy-cashu.nostr.*]
+ignore_errors = True